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US5394435A
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Diversity for direct-sequence spread spectrum systems
Assignee: AT&T Inc
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Filing: 1994-02-22
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Granted: 1995-02-28
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Expires: 2014-02-22
Abstract
Abstract An invention for providing diversity for direct sequence spread spectrum wireless communication systems is presented. The invention provides a transmitting technique for communicating a first signal comprising one or more segments to a receiver with use of a plurality of M antennas. The first signal includes one or more signal segments. The technique comprises forming M copies of the first signal; for a segment of a signal copy, weighting each of two or more sub-segments of the segment with a distinct signal, wherein a sequence of the distinct weighting signals for the segment is distinct from sequences of signals weighting the same segment of one or more other signal copies; and for each of M weighted signal copies, transmitting a signal to the receiver using a distinct antenna, the transmitted signal based on the weighted signal copy. Illustratively, the first signal is a spread spectrum signal. Moreover, the process of weighting comprises applying a phase shift to a sub-segment. The invention further provides a receiving technique which comprises, for a copy of a received signal, despreading a segment of the received signs, demodulating a plurality of sub-segments of the despread signal segment, wherein each sub-segment is demodulated with use of one or more estimated communication channel characteristics corresponding to the sub-segment, and forming a summation signal reflecting a summation of a plurality of demodulated sub-segments. The receiving technique further comprises forming a signal reflecting a signal segment value, the formed signal based on one or more summation signals. The step of demodulating may precede the step of despreading in some embodiments.
Inventors
- 👤 Vijitha Weerackody
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:08
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/06; H04B7/0613
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
143 words
A method of operating a direct-sequence spread spectrum transmitter for communicating a first signal to a receiver, said transmitter including a plurality of antennas, said first signal including one or more signal segments, the method comprising the steps of: forming a plurality of second signals, each of the second signals formed based on two or more sub-segments of a given segment of the first signal and two or more corresponding weighting signals, wherein a sequence of weighting signals used in forming one of said second signals is distinct from one or more other sequences of weighting signals used in forming one or more other of said second signals; and transmitting a plurality of signals each with a distinct antenna, wherein at least two of said plurality of transmitted signals represent second signals which are formed with use of distinct sequences of weighting signals.
Claim 2
Independent Claim
143 words
A method of operating a direct-sequence spread spectrum transmitter for communicating a first signal to a receiver, said transmitter including a plurality of antennas, said first signal including one or more signal segments, the method comprising the steps of: forming a plurality of second signals, each of the second signals formed based on two or more sub-segments of a given segment of the first signal and two or more corresponding weighting signals, wherein a sequence of weighting signals used in forming one of said second signals is distinct from one or more other sequences of weighting signals used in forming one or more other of said second signals; and transmitting a plurality of signals each with a distinct antenna, wherein at least two of said plurality of transmitted signals represent second signals which are formed with use of distinct sequences of weighting signals.
Claim 3
Dependent Claim
58 words
The method of claim 1 wherein the step of forming a plurality of second signals comprises forming at least one of said second signals based on a sequence of two or more weighting signals, each of which two or more weighting signals equals unity, such that the two or more corresponding sub-segments of the first signal are unaltered.
Claim 4
Dependent Claim
33 words
The method of claim 1 wherein a second signal is formed by applying a phase shift to at least one sub-segment of the first signal, the phase-shift specified by a corresponding weighting signal.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the first signal is a spread spectrum signal which reflects the product of an information signal and a signature sequence signal.
Claim 6
Dependent Claim
15 words
The method of claim 4 wherein a signal segment represents a discrete information signal value.
Claim 7
Dependent Claim
33 words
The method of claim 1 wherein the step of transmitting a plurality of signals comprises forming a spread spectrum signal which represents a product of a second signal and a signature sequence signal.
Claim 8
Dependent Claim
137 words
A direct-sequence spread spectrum transmitter for communicating a first signal to a receiver, said first signal including one or more signal segments, the transmitter comprising: means for forming a plurality of second signals, each of the second signals formed based on two or more sub-segments of a given segment of the first signal and two or more corresponding weighting signals, wherein a sequence of weighting signals used in forming one of said second signals is distinct from one or more other sequences of weighting signals used in forming one or more other of said second signals; a plurality of antennas; and means for transmitting a plurality of signals each with a distinct antenna, wherein at least two of said plurality of transmitted signals represent second signals which are formed with use of distinct sequences of weighting signals.
Claim 9
Dependent Claim
137 words
A direct-sequence spread spectrum transmitter for communicating a first signal to a receiver, said first signal including one or more signal segments, the transmitter comprising: means for forming a plurality of second signals, each of the second signals formed based on two or more sub-segments of a given segment of the first signal and two or more corresponding weighting signals, wherein a sequence of weighting signals used in forming one of said second signals is distinct from one or more other sequences of weighting signals used in forming one or more other of said second signals; a plurality of antennas; and means for transmitting a plurality of signals each with a distinct antenna, wherein at least two of said plurality of transmitted signals represent second signals which are formed with use of distinct sequences of weighting signals.
Claim 10
Dependent Claim
60 words
The transmitter of claim 7 wherein the means for forming a plurality of second signals comprises means for forming at least one of said second signals based on a sequence of two or more weighting signals, each of which two or more weighting signals equals unity, such that the two or more corresponding sub-segments of the first signal are unaltered.
Claim 11
Dependent Claim
39 words
The transmitter of claim 7 wherein the means for forming a plurality of second signals comprises means for applying a phase shift to at least one sub-segment of the first signal, the phase-shift specified by a corresponding weighting signal.
Claim 12
Dependent Claim
27 words
The transmitter of claim 7 wherein the first signal is a spread spectrum signal which reflects the product of an information signal and a signature sequence signal.
Claim 13
Dependent Claim
15 words
The transmitter of claim 10 wherein a signal segment represents a discrete information signal value.
Claim 14
Dependent Claim
35 words
The transmitter of claim 7 wherein the means for transmitting a plurality of signals comprises means for forming a spread spectrum signal which represents a product of a second signal and a signature sequence signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-27 | 1998-08-29 | 1999-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-27 | 2002-08-29 | 2003-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-27 | 2006-08-29 | 2007-02-28 | $7700.00 | Window Closed / Lapsed |